This nonprovisional application claims priority under 35 U.S.C. xc2xa7119(a) on Patent Application No. 2001-334312 filed in JAPAN on Oct. 31, 2001, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a pellicle and a producing method of a mask having a pellicle attached to a substrate such as the mask or a reticle (mask and reticle are generically called xe2x80x9cmaskxe2x80x9d, hereinafter).
2. Description of the Related Art
In a photolithography process, using a photomask or a reticle having a glass plate surface on which a circuit pattern is formed by a deposition film such as chromium, the circuit pattern is transferred, by means of exposure, onto a silicon wafer on which a resist is applied. In this process, if the exposure is performed in a state in which a foreign matter such as dust is attached to the circuit pattern on the mask, the foreign matter is transferred also onto the wafer, and a failed wafer is adversely produced. Especially when the exposure is performed by a stepper, a possibility that all chips formed on a wafer become failed chips is high, and the adhesion of foreign matters onto a wafer is a serious problem. Thereupon, a pellicle through which exposure light excellently passes is mounted to a mask, thereby preventing dust from attaching to the mask.
Usually, a mask is produced through the following five processes:
(1) a process for cleaning a mask;
(2) a process for inspecting the mask, i.e., for checking whether a circuit is formed as designed and whether a foreign matter is not attached to the mask;
(3) a process for adhering a pellicle to the mask;
(4) a process for inspecting the mask with the pellicle; and
(5) a process for shipping the mask.
Usually, in the process (2), it is inspected whether the mask is produced as designed and whether a foreign matter is not attached to the mask. Only accepted masks are brought into the process (3). Thereafter, in the process (4), a pellicle is adhered to the mask, and then it is inspected whether a failure is not generated in the mask and whether a foreign matter is not mixed. Only accepted masks are brought into the shipping process. The pellicles are peeled off from failed masks, and such masks are returned to the process (1), where the masks are reused. The pellicles are damaged in some cases at the time of the peeling-off operation and thus, they are discarded.
Although a computer system is used for the inspection, it is indispensable for people to inspect the masks by himself or herself eventually, and the similar inspections must be carried out as many as twice before shipment, which increases costs industrially. Further, from the failed masks with pellicles generated in the inspection of the process (4), the pellicles are peeled off and then, the masks are returned to the cleaning process (1), but since the pellicles can not be reused, there are realities that the pellicles must be discarded.
Japanese Patent Application Laid-open No. 7-120931 discloses that an adhesive whose adhesion force is weakened by heating and/or light irradiation is used as an adhesive for fixing a pellicle to a reticle, the pellicle is adhered to the reticle by this kind of adhesion layer, and if this adhesion layer is heated or irradiated with light, the adhesion force of the adhesion layer is weakened and thus, the pellicle can easily be peeled off from the reticle. According to this technique, however, in order to peel off the pellicle from the reticle, it is necessary to carry out an operation for changing an environment condition for the mask with the pellicle or the like.
Therefore, it is a main object of the present invention to provide a pellicle and a producing method of a mask with a pellicle, in which the number of inspections can be reduced, and the pellicle can be peeled off from a mask and reused after the pellicle is once attached to the mask.
According to a first aspect of the present invention, there is provided a pellicle, comprising:
a pellicle frame having one end face and the other end face and being provided at its central portion with an opening, the other end face of the pellicle frame being provided with an adhesion layer;
a pellicle film stretched over and attached to the one end face of the pellicle frame; and
at least two liners adhered on the adhesion layer, wherein
the at least two liners can be respectively peeled off from the adhesion layer, and when the at least two liners are respectively peeled off from the adhesion layer, a portion of the adhesion layer to which each of the liners was adhered is exposed.
According to a second aspect of the present invention, there is provided a producing method of a mask with a pellicle, comprising
temporarily adhering a pellicle to a mask in a state in which the pellicle can be peeled off from the mask, the pellicle having a pellicle frame provided at its central portion with an opening, a pellicle film stretched over and attached to one end face of the pellicle frame, and an adhesion layer provided on the other end face of the pellicle frame,
inspecting the mask in the temporarily adhered state,
finally adhering the pellicle to the mask by the adhesion layer to produce the mask with the pellicle if the mask is accepted in the inspection, and peeling off the pellicle from the mask if the mask is not accepted in the inspection and reusing the pellicle to produce a mask with the pellicle.
According to a third aspect of the present invention, there is provided a producing method of a mask with a pellicle, comprising:
preparing a pellicle having a pellicle frame provided at its central portion with an opening, a pellicle film stretched over and attached to one end face of the pellicle frame, an adhesion layer provided on the other end face of the pellicle frame, and at least two liners adhered onto the adhesion layer,
removing at least one of the at least two liners from the pellicle frame to expose a portion of the adhesion layer, and temporarily adhering the pellicle to a mask through the exposed adhesion layer, and
removing at least one of the remaining liners or the remaining liner, thereby finally adhering the pellicle to the mask.
According to a fourth aspect of the present invention, there is provided a producing method of a mask with a pellicle, comprising:
preparing a pellicle having a pellicle frame provided at its central portion with an opening, a pellicle film stretched over and attached to one end surface of the pellicle frame, an adhesion layer provided on the other end face of the pellicle frame, and a main liner and a sub-liner laminated on each other such that a portion of the main liner is exposed from the sub-liner, the sub-liner being adhered directly to the adhesion layer, the main liner being also adhered directly to the adhesion layer at the portion of the main liner which is exposed from the sub-liner, the main liner and the sub-liner being capable of being peeled off from the adhesion layer separately,
peeling off the main liner from the adhesion layer, and temporarily adhering the pellicle to a mask by the adhesion layer exposed from the sub-liner, and
thereafter, peeling off the sub-liner from the adhesion layer in the temporarily adhered state, and finally adhering the pellicle to the mask by the adhesion layer.